Carburetor

ABSTRACT

A fuel carbureting device having a housing with an air intake passage therethrough and an engine mounting fixture and utilizing a unique fuel-metering and throttle system including an elongated hollow fuel tube axially movable in the housing and coupled to a source of fuel at an outer end and having an open inner end into which an elongated flat-tapered fuel metering needle is disposed, the needle being essentially fixed in position except for slight axial movement by rotation of an external adjustment knob; the system also including a sliding throttle plate having a relatively large opening through its planar surface registrable with the air intake passage to a degree determined by the throttle linkage, opening of the carburetor&#39;&#39;s throttle being accomplished through linkage which causes the plate to move so that more of the opening therein is exposed to the air intake passage, throttle plate movement also causing movement of the fuel tube in an axial direction toward the tip of the tapered needle to enlarge the fuel-metering orifice at the inner end of the fuel tube.

United/States Patent 191 ,9 Carter 111 3,822,058 [451 July 2,1974

FOREIGN PATENTS OR APPLICATIONS 1,219,207 1/1971 1 Great Britain 261/44R Primary Examiner-Tim R. Miles Attorney, Agent, or FirmSpensley, Horn&' Lubitz 57] ABSTRACT A fuel carbureting device having a housing withan air intake passage therethrough and an engine mounting fixture andutilizing a unique fuel-metering and throttle system including anelongated hollow fuel tube axially movable in the housing and coupled toa source of fuel at an outer end and having an open inner end into whichan elongated flat-tapered fuel metering needle is disposed, the needlebeing essentially fixed in position except for slight axial movement byrotation of an external adjustment knob; the system also including asliding throttle plate having a relatively large opening through itsplanar surface registrable with the air intake passage to a degreedetermined by the throttle linkage, opening of the carburetors throttlebeing accomplished through linkage which causes the plate to move sothat more of the opening therein is exposed to the air intake passage,throttle plate movement also causing movement of the fuel tube in anaxial direction toward the tip of the tapered needle to enlarge thefuel-metering orifice at the inner end of the fuel tube.

1 Claim, 10 Drawing Figures 1 l 1 I //////X 4/ ///I 73 V B 11- J 4| 3927 31 2:5 i \1 43 4o 65 a 1 l T W A I A 11 f I n 62-.- ii 69 ///////l//1 CARBURETOR BACKGROUND OF THE INVENTION Most conventional carburetingdevices use a liquid fuelable reservoir in conjunction with throttle andfuelmetering arrangements. Although these devices are used extensivelyin the automobile industry, their efficiency is generally low andresults in low fuel mileage, unclean exhaust emission and high frequencyof costly tearing down and cleaning procedures. Recently, a carburetingdevice without a liquid fuelable reservoir has been developed, but itssystem for regulating the mixing of fuel and air is mechanicallycomplicated and relatively expensive to manufacture. This type ofcarburetor has also experienced problems when used on a high compressionengine where the suction force created within this type of engine tendsto cause the carbure tors sliding throttle mechanism to jam.

SUMMARY OF THE INVENTION In view of the foregoing factors and conditionscharacteristic of the prior art, it is a primary object of the presentinvention to provide a new and improved carburetor for regulating themixing of fuel and air.

Another object of the present invention is to provide a carburetorwherein the mixing of air and fuel can be easily regulated and adjusted.

Still another object of the present invention is to provide a carburetorfor regulating the mixing of fuel and air which is comprised of a fewsimple parts and is easily assembled.

Yet another object of the present invention is to provide aninexpensively maintainable carburetor of the type having no internalfuel reservoir.

Still a further object of the present invention is to provide animproved carburetor for regulating and mixing of fuel and air to highcompression engines.

According to an embodiment of the present invention, a carburetor isprovided for adjustably controlling the amount of fuel and airintroduced to an engine, the carburetor including a carburetor housingwith an air intake passage and an axially aligned air-fuel exit passageand with an elongated hollow fuel delivery tube axially movably mountedin the housing, the tube including an external fuel input end and aninternal fuel metering end. The carburetor also includes a throttleplate having parallel broad planar surfaces with a throttle openingtherethrough, the plate being slidably disposed in the housing with thethrottle opening registerable with the intake and exit passages to adesired changeable degree. The plate includes throttle means for movingthe plate and the tube in a direction essentially parallel to thelongitudinal axis of the tube. An elongated fuel-metering needle havingan elongated flat tapered end portion extends into the internalfuelmetering end of the tube and defines at the internal end anapproximate elliptical fuel-metering orifice which essentially linearlyenlarges with movement of the plate and tube in a throttle-openingdirection exposing more of the plates throttle-opening to the intake andexit passages. I

The features of the present invention which are believed to be novel areset forth with particularity in the appended claims. The presentinvention, both as to its organization and manner of operation, togetherwith further objects and advantages thereof, may best be understood bymaking reference to the following description taken in conjunction withthe accompanying drawings in which like reference characters refer tolike components in the several views.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic drawing of abasic carbureting device of the type not incorporating a liquid fuelreservoir;

FIG. 2 is a prospective view of a carbureting device constructed inaccordance with the present invention;

. FIG. 3 is a sectional view of the carburetor shown in FIG. 2, takenalong line 33;

FIG. 4 is a sectional view taken along line 44 of FIG. 2;

FIGS. 5a and FIG. 5b are enlarged cross-sectional illustrations of thefuel-metering needle and tube that define a changeable fuel-meteringorifice therebetween;

FIG. 6 is a plan view of the throttle value plate member of thecarburetor device shown in FIGS. 3 and 4;

FIGS. 7 and 8 are views showing the opposite ends of the throttle valueplate of FIG. 6; and

FIG. 9 is a plan view illustrating the relationship between thefuel-metering orifice and the throttle value plate with respect to thecarburetors throat when the mechanism is in a partial open throttlecondition.

DESCRIPTION OF THE INVENTION Referring now to the drawing and moreparticularly to FIGS. 1 and 2, there is shown a carbureting device orcarburetor 10 having an air intake 11, an air throttle mechanism 12, afuel intake 13, a fuel-metering mechanism l4, and an engine mountingdevice or fixture 15. Referring now also to FIGS. 3 and 4, it can beseen that the air throttle mechanism 12 and the fuel-metering mechanism14 are incorporated in the carburetors housing 16 which basicallyincludes a central elongated rectangular plate 17 having a relativelylarge rectangular opening 18 appropriately cast or machined therein, theopening 18 being bounded by a first end wall 19, an opposite second endwall 20, and :side walls 21.

Mounted above and below the plate 17 by machine screws 22 or the like,in order to create a chamber 23 therebetween, are upper and lower plates25 and 26, respectively. A bore 27, along the longitudinal axis (notshown) of the carburetor 23, is provided in order to slideably accept afuel delivery end 28 of a hollow cylindrical liquid fuel tube 31therethrough. A conventional flexible fuel hose connector 32 is suitablymounted to the tubes end 28 to convey fuel to the interior of the tube31. As can best be seen in FIGS. 3 and 4, a compressible helical coilspring 33 is mounted within the chamber 23 about the tube 31 and betweenthe first end wall 19 and an annular anchor flange 34 which is fixedlyattached near an end 35 of the tube 31.

The fuel-metering mechanism 14 includes, along with the liquid fuel tube31, a fuel-metering needle 36 having a flat, gradually tapering end 37and an opposite, threaded end 38. A fuel-metering adjustment knob 39 ismounted on the needles end 38 by a set screw 39a, as illustrated in FIG.4.

An enlarged sleeve 40 is mounted in the cavity 23, extending through abore 41 in the second end wall 20. The sleeves open end 42 lies adjacentthe knob 39 and its other end 43 is crimped or otherwise provided with adecreased diameter opening through which the needle 36 extends. Adefonnable plastic cylinder 44 is disposed within the sleeve 40, and adetent screw 45 is threadably housed in a threaded hole 46 in thehousing and extends through an aperture 47 in the sleeve 40 to contactand deform inwardly the plastic cylinder 44. This effectively causes theinner wall of the cylinder 44 to enter the grooves of the needlesthreaded end 38 and act as a threaded nut so that rotation of the needleabout its longitudinal axis will cause its axial movement. The sleevescrimped end 43 is sealed against fluid loss by a conventional resiliento-ring 48, usually rubber, disposed between the end 43 and the adjacentend of the plastic cylinder 44. In its extreme inward position as urgedby spring 33, the tubes end 35 is pressed against the o-ring 48 tocompletely seal off fuel flow from the tube 31 (see FIGS. 3 and 4).

As will be described later, the fluid fuel tube 31 may be caused to moveaxially in the direction indicated by an arrow A. This action moves theend 35 of the fuel tube 31 relative to the fuel-metering needle 36towards its diminishing thickness end 37. This relative movementeffectively changes the size of an orifice 49 defined by a flat surface50 of the flat tapered needle 36 and an inner wall 31a of the hollowfluid fuel tube 31. For example, FIGS. a and 5b illustrate the enlargingof the fuel-metering orifice 49 from a relatively small opening in FIG.5a to a relatively larger opening in FIG. 5b, with relative movement ofthe fuel tube 31 in the direction indicated by arrow A. This relativemovement can also be obtained, over a lesser range, by theaforementioned axial movement of the needle 36 through rotation of theadjustment knob 39.

With reference now to the air throttle device 12 of thepresentcarburetor 10, it includes a sliding throttle valve plate 51 ofany suitable material such as a phenolic or metal. The plate 51 isgenerally rectangular in shape having a length less than the length ofthe chamber 23 and a thickness and width dimension to slideably fit inthe chamber 23, as shown in FIGS. 3 and 4. The plate 51 includes athrottle opening 52 through the plates broad surfaces, and an axial bore53, as illustrated in more detail in FIGS. 6-8. The plate 51 is alsoprovided with a pair of roller bearings 54 mounted on cantilevered pins55 extended into appropriate notches 56 in the sides 57 of the plate 51.These bearings tend to decrease frictional forces between the broadsurfaces of the sliding plate and the inner walls of the housings upperand lower plates 25 and 26. This is especially advantageous when thecarburetor is mounted on a relatively high compression engine whichcreates a high pressure differential between the throat 58 of the airintake 11 and the matching diameter throat 59 of the engine mountingfixture 15.

The plate further includes a transverse bore 60 to accommodate an anchorrod 62 terminating an accelerator cable 63, the cable extending througha slot 64 which lies midway between and parallel to the broad surfacesof the sliding plate 51 and extends between the axial bore 53 andtransverse bore 60. A second axial bore 65 is disposed centrally in anend wall 66 of the plate 51 adjacent the chambers second end wall 20,and is dimensioned to slidably accept the hollow sleeve 40.

At the sliding plates opposite end 67, the axial bore 53 has a diameterto accept the tube 31, the helical coil spring 33, and the anchor flange34. However, the bore 53 has a reduced diameter portion 68 allowingcommunication between the larger diameter portion of the bore 53 and thethrottle opening 52 for only that portion of the tube 31 extendingbeyond the anchor flange 34.

In the position of the sliding throttle plate 51 shown in FIGS. 3 and 4,it can be seen that the plates broad surfaces are totally disposedbetween the throats of the air intake 11 and the mounting fixture 16 toeffectively cut off the flow of air through the carburetor 10. As notedbefore, the spring 33 biases the fuel tube 31 in the direction (1B)opposite to that indicated by arrow A. The tubes anchor flange 34thereby exerts pressure in this direction against the sliding throttleplate 51 at the reduced diameter portion 68 where the flange 34 abutts.Thus, the normal closed throttle condition will exist both for the airthrottle and fuel-metering mechanisms 12 and 14 until an external forceis exerted on the plate 51 by the placing of a tension force on thethrottle control cable 63 at a point beyond the housingmountedconventional adjustable Boden cable terminal fixture 69.

The pulling of the control cable 63 in the direction of the arrow A willcause the sliding plate 51 to push against the anchor flange 34 andthereby cause the movement of both the plate 51 and the fuel tube 31.This moves the throttle opening 52 into greater and greatercommunication with the throats of the air intake and mounting devices 11and 15, while at the same time causing relative movement between thetubes end 35 and the flat tapered fuel-metering needle 36. Thus, airpassage through the carburetor 10, as governed by the throttle mechanism12, is simultaneously increased with a predetermined increase of fuelbeing metered by the carburetors mechanism 14, as clearly illustrated inFIG. 9. It will be noted from the last mentioned figure that the fuelexiting end 35 of the tube 31 is always positioned in the throttleopening 52 adjacent the air passage through the throats 58 and 59 toaffect the most efficient mixing of the air and fuel.

The carburetor is provided with a fine fuel-metering adjustment operablethrough the aforementioned knob 39 to increase or decrease the amount offuel passing through the orifice 49. An engine idling adjustment is alsoprovided by rotating an adjustment screw 70 (see FIG. 4). The screw 70has a threaded shank portion 71 restrained by a spring 71a andthreadably engaged in a threaded hole in the upper housing plate 25adjacent the second end wall 20 of the plate 17. The shank portions end72 is tapered to a point, the conical surface of which engages a bevelednotch 73 in the upper planar surface of the sliding throttle plate 51,shown in FIG. 3. With right hand thread, clockwise rotation of the screw70 moves the shank portion 71 inwardly and the screws end 72 pushesagainst the surface of the notch 73 to move the plate 51 away from theend wall 20. It can thus be seen that the throttle plates maximumexcursion in the direction B is limited bythe adjustment screw 70 for adesired engine idling speed.

From the foregoing it should be evident that there has herein beendescribed a relatively simple, compact, and a lightweight carburetorthat is highly-efficient and economical to fabricate and maintain andwhich may be used on high compression engines.

The materials used in fabricating the invention are not critical and anymaterial generally considered to be suitable for a particular componentand function may be substituted for the material specifically identifiedherein. For example, the carburetors housing and fixtures mountedthereon may be molded or machined from a light-weight metal such asaluminum, for example, and ionized if desired.

It should be realized from the above description that the invention issusceptible to modifications and other embodiments. Furthermore, itshould be noted that the various components shown in the figures are notdrawn to scale. Accordingly, it is intended that the foregoingdisclosure and showing in the drawings shall be considered only asillustrations of the principles of this invention.

What is claimed is:

1. A carburetor for adjustably controlling the amount of fuel and airintroduced to an engine on which the carburetor is mounted comprising:

a. a carburetor housing with an air intake passage and an axiallyaligned air-fuel exit passage;

b. an elongated hollow fuel delivery tube axially movably mounted insaid housing, said tube including an external fuel input end and aninternal fuelmetering end;

c. a throttle plate having parallel'broad planar surfaces with athrottle opening therethrough, said plate being slidably disposed insaid housing with said throttle opening registerable with said intakeand exit passages to a desired changeable degree, said plateincludingthrottle means for moving said plate and said tube in adirection essentially parallel to the longitudinal axis of said tube andhaving an elongated bore therethrough axially aligned with thelongitudinal axis of said tube;

d. an elongated fuel-metering needle having an external end and anaxially opposite elongated flattapered end portion, said needle passingthrough said bore and extending into said internal fuelmetering end ofsaid tube and defining at said internal end a fuel-metering orificewhich essentially linearly enlarges with movement of said plate and tubein a throttle-opening direction exposing more of said throttle openingto said intake and exit passages, said needle including a threadedportion adjacent said external end;

e. fuel adjustment means for axially moving said needle relative to saidtube coupled to the external end of said elongated fuel-metering needleand including a hollow sleeve with a deformable hollow liner coaxiallydisposed in said sleeve, said sleeve slidably extending through saidelongated bore in said plate and said needle extending through the borein said hollow liner;

f. a rotatable adjustment knob fixedly attached to said external end ofsaid needle, said needle including a threaded portion adjacent saidexternal end; and

g. a detent screw mounted in said housing passing through an aperture insaid sleeve and deforming inwardly a portion of said liner to contactsaid threaded portion of said needle whereby said needle is movedaxially with the rotation of said adjustment knob.

1. A carburetor for adjustably controlling the amount of fuel and airintroduced to an engine on which the carburetor is mounted comprising:a. a carburetor housing with an air intake passage and an axiallyaligned air-fuel exit passage; b. an elongated hollow fuel delivery tubeaxially movably mounted in said housing, said tube including an externalfuel input end and an internal fuel-metering end; c. a throttle platehaving parallel broad planar surfaces with a throttle openingtherethrough, said plate being slidably disposed in said housing withsaid throttle opening registerable with said intake and exit passages toa desired changeable degree, said plate including throttle means formoving said plate and said tube in a direction essentially parallel tothe longitudinal axis of said tube and having an elongated boretherethrough axially aligned with the longitudinal axis of said tube; d.an elongated fuel-metering needle having an external end and an axiallyopposite elongated flat-tapered end portion, said needle passing throughsaid bore and extending into said internal fuel-metering end of saidtube and defining at said internal end a fuel-metering orifice whichessentially linearly enlarges with movement of said plate and tube in athrottleopening direction exposing more of said throttle opening to saidintake and exit passages, said needle including a threaded portionadjacent said external end; e. fuel adjustment means for axially movingsaid needle relative to said tube coupled to the external end of saidelongated fuel-metering needle and including a hollow sleeve with adeformable hollow liner coaxially disposed in said sleeve, said sleeveslidably extending through said elongated bore in said plate and saidneedle extending through the bore in said hollow liner; f. a rotatableadjustment knob fixedly attached to said external end of said needle,said needle including a threaded portion adjacent said external end; andg. a detent screw mounted in said housing passing through an aperture insaid sleeve and deforming inwardly a portion of said liner to contactsaid threaded portion of said needle whereby said needle is movedaxially with the rotation of said adjustment knob.